PROJECT SUMMARY/ABSTRACT Dr. Rusley is pursuing this K23 Mentored Patient-Oriented Research Career Development Award to facilitate his transition to an independent HIV prevention scientist. His career goal is to eliminate health disparities among adolescents and young adults at risk for HIV. He has a background in pediatric and adolescent medicine, clinical research, public health, and motivational interviewing (MI) that create a strong foundation for the proposed training and research plan. He has assembled a highly accomplished and diverse team of mentors with complementary expertise in adolescent sexual minority male (ASMM) health, HIV prevention including pre-exposure prophylaxis (PrEP), behavioral interventions, family-based interventions, implementation science, and ethical issues in adolescent sexuality research. These mentors, along with an excellent and highly-interdisciplinary research environment at Brown University and Rhode Island Hospital will facilitate his training and research plan, as well as his transition to an independent, NIH- funded researcher. Given the disproportionate burden of HIV borne by sexual minority males in the US?especially young men?and the fact that most of these men have their first sexual experience as adolescents, ASMM are a key population for HIV prevention interventions. However, there are very few evidence-based HIV prevention interventions for this group, in part due to complexities with parental involvement in research. Many experts have called for inclusion of parents in HIV prevention interventions for ASMM, given the key protective roles they can play in their children?s lives; yet there are no family-based HIV prevention interventions for ASMM in the US. PrEP is a highly effective HIV prevention tool that has recently been added to the existing HIV prevention toolkit with FDA approval for adolescents in 2018, yet uptake among ASMM has been low. The few studies that address this gap in PrEP uptake among ASMM suggest possible barriers may include: concerns about disclosure of sexuality to parents (?outing?), knowledge of and motivation to use PrEP, and lack of access to primary care clinicians who prescribe PrEP. Therefore, we will develop a family-based HIV prevention intervention for ASMM that can be used in primary care settings. First, we will conduct a formative evaluation using in-depth individual interviews with ASMM (n=12-15) and parents (n=12-15) to determine barriers and facilitators to the success of the planned intervention (Specific Aim (SA) 1). Second, we will adapt an existing evidenced-based, motivational interviewing (MI) intervention to include PrEP education and counseling, as well as a family-based component (a video-based education module about parental support, sexuality communication, and PrEP as HIV prevention). We will then pilot the intervention with ASMM-parent dyads (n=10) (SA2). Finally, we will conduct an exploratory randomized trial of the intervention with ASMM-parent dyads (n=100) to test its effect on PrEP uptake at baseline and 8-week follow up, and to determine feasibility and acceptability (SA3). Overall, the intervention will reach a difficult to access population, build protective parent relationships, and increase PrEP uptake among a key population at risk, thereby reducing new HIV infections. The proposed training and research plan will provide Dr. Rusley the experience and mentoring needed to expand his skills and become an independent and leading HIV prevention scientist.